The present invention relates to chucks, and more particularly, to a chuck for holding a hub assembly and rotating a component of the assembly.
Automotive manufacturers have turned more and more to packaged components in the assembly of their vehicles. Often, outside suppliers provide these components, thus saving the vehicle manufacturers the expense and problems of maintaining manufacturing facilities for them. The hub assemblies for the road wheels of the vehicles represent one type of component which lends itself well to outside manufacture.
Many automobiles and sport utility vehicles of current manufacture have all of their road wheels independently suspended. Packaged hub assemblies function well for mounting the wheels of these vehicles on the independent suspension systems of the vehicles. The typical hub assembly has a hub provided with a flange, to which a road wheel and a brake disk or drum are fastened, and a spindle which projects from the flange into a housing. Here the spindle rotates on a bearing that is within the housing. The housing in turn is bolted to a component of the suspension system, such as a steering knuckle. The bearing normally takes the form of a double row tapered roller bearing or a double row angular contact ball bearing. Either will accommodate radial loads and in addition thrust loads in both axial directions. Moreover, the manufacturers of the hub assemblies normally set the bearings to a condition of slight preload, thus eliminating all radial and axial clearances in the bearings. This enables the hub of a hub assembly to rotate about an axis that is fixed with respect to the housing, but does not eliminate runout (wobble) in the hub flange. And runout in the flange will translate into runout in a brake disk which is against the flange. Runout in a brake disk causes uneven brake wear and creates a pulsating sensation, known as xe2x80x9cbrake judderxe2x80x9d, when the brakes are applied.
U.S. Pat. No. 6,158,124 discloses machining the friction surface of a brake disk while it is fastened to its hub and the hub is rotated on its bearing, all while the housing is held fast. U.S. Pat. No. 6,071,180 discloses grinding the face of a hub flange in similar manner. However, gripping the hub to rotate it has always proved troublesome in that the axis of the hub may not coincide with the axis of rotation established by the bearing. This makes it difficult to couple the hub with a chuck designed to rotate it.
The present invention resides in a chuck having a fixed member that carries jaws that are capable of gripping the housing of a hub assembly and a rotatable member to which an arbor is coupled, with the arbor being capable of engaging a hub that rotates in the housing on a bearing. The arbor has the capacity to shift radially with respect to the rotatable member to accommodate misalignment between the axes of rotation for the rotatable member and the hub. The invention also resides in the combination of the chuck and the hub assembly.